Individualized lesion-oriented test-bolus arterial-phase CT improves lesion enhancement and conspicuity in hepatocellular carcinoma.

[BACKGROUND] Accurate arterial-phase timing in contrast-enhanced CT (CECT) is critical for evaluating hepatocellular carcinoma (HCC). Standard-delay methods may fail to capture peak arterial enhancement due to interindividual hemodynamic variability, potentially reducing lesion conspicuity. This study evaluated whether individualized, dynamically tailored arterial-phase CT (t-CT) based on test-bolus peak in the lesion or, if not feasible, within the portal vein, improves quantitative enhancement and lesion conspicuity compared with standard-delay CT (s-CT).

[MATERIALS AND METHODS] This intraindividual study included 39 patients with 60 HCC lesions who underwent both t-CT and s-CT. Maximum and mean lesion attenuation (HU, HU), relative lesion-to-liver attenuation (relative HU, relative HU), and image noise were measured. Four readers rated lesion conspicuity on a five-point Likert scale; inter-reader agreement was assessed using weighted κ, Krippendorff's α, and intraclass correlation coefficient (ICC).

[RESULTS] All quantitative parameters differed significantly between protocols. HU was greater in t-CT than on s-CT (151.0 [130.0-199.8] HU vs 113.5 [97.0-150.0]; p < 0.001), as well as HU (124.5 [104.5-144.8] HU vs 90.5 [79.8-112.8]; p < 0.001), relative HU (1.9 [1.7-2.3] vs 1.8 [1.5-2.2]; p = 0.009) and relative HU (1.6 [1.4-1.9] vs 1.4 [1.3-1.7]; p < 0.001). Image noise was lower on t-CT than on s-CT (8.4 [6.7-9.7] vs 11.1 [9.6-12.9]; p < 0.001). Median lesion conspicuity was higher on t-CT (4.0 vs 3.0; p < 0.001).

[CONCLUSION] Individualized lesion-oriented test bolus arterial-phase timing in CECT demonstrated higher lesion attenuation, greater lesion-to-liver contrast, lower image noise, and higher visibility compared with standard arterial-phase timing in HCC.